1. Field of the Invention
This invention relates to a method for detecting intracranial microbleeding by continuing microshifting of a person's brain within the cranium.
2. The Problem
Head trauma which appears to be minor, that is an injury resulting from an impact to the skull, such as by a blow or a fall or in a motorcycle accident, may have serious or even fatal consequences. If the skull impact is sufficiently severe to cause a brain concussion resulting in at least temporary and transient brain malfunction, the patient would be held in a hospital probably for several days for testing and observation. On the other hand, if the trauma appears to be minor and visual examination in the emergency room of a hospital does not reveal any problem or cause for concern, the patient will probably be discharged within an hour or two.
It is possible that the trauma may have displaced the cranium relative to the brain, particularly sideways, sufficiently to rupture one or more small veins, the bleeding from which would normally be undetected by the usual emergency room visual examination. If the patient is sent home, continued bleeding can cause an accumulation of blood in a pocket or hematoma at one side of the brain which initially would shift the brain to an eccentric position in the cranium. If the bleeding continued to a sufficient extent and for a sufficient period of time, the pressure of the accumulated blood against the brain could cause drowsiness or even cause the patient to fall into a coma.
The medulla oblongata forming the lower portion of the brain passes through the foramen magnum, which is the large opening in the occipital bone that forms the posterior part of the skull, to become the spinal cord. The brain is readily deformable and continued pressure on it by the progressive accumulation of blood in an intracranial hematoma could force the medulla oblongata farther into the foramen magnum. The medulla oblongata is tapered downwardly and contains the respiratory center which controls breathing. The continued pressure on the brain may wedge the medulla oblongata into the foramen magnum, causing sufficient pressure on it to result in respiratory arrest, usually while the patient is unconscious, and consequent death within about twenty-four hours after the injury.
Prior Art
If medical personnel were alerted to the abnormal shift of the brain relative to the cranium caused by the accumulation of blood in a pocket at one side of the cranium, diagnosis could be effected by taking a computer assisted tomography (CAT) picture of the head, but such a CAT scan probably would not disclose a microshift of the brain but only a substantial shift effected by continued bleeding into the cranial pocket for several hours. Such a diagnosis could be effected in a hospital if the patient remained for a sufficient period of time
After proper diagnosis, the blood accumulation condition could be remedied by a surgeon cutting an aperture in the skull (trephination) at the location of the hematoma and installing a drain to allow blood to flow out of the pocket in the skull, thereby relieving pressure against the brain and allowing it to resume its proper position within the cranium. When the pressure on the brain is relieved by draining blood, the patient rouses. Such surgical procedure would be followed, however, only on the basis of an appropriate diagnosis.
Basic Problem
The basic problem, therefore, is to determine when a patient might be at risk of having a continuing brain displacement relative to the cranium which would dictate that the patient remain in the hospital for a day or two for evaluation and examination. The normal procedure, as mentioned above, would be to release the patient from the emergency room in an hour or two, during which time there normally would be no evidence of the brain being shifted relative to the cranium by pressure of blood accumulated in a pocket.
It has been determined that, when blood escapes from a ruptured blood vessel or blood vessels in the skull, such blood may accumulate slowly in a pocket and effect pressure against the brain which would cause it to move sideways away from the side of the cranium where the pocket is formed. Such brain shift would be very slow, such as for a distance of perhaps one centimeter in ten hours, or about one millimeter per hour, or seventeen microns per minute. If such minute shifting could be detected, it would forewarn medical personnel that a problem of substantial brain shift could occur over a period of several hours, so that it would be desirable to retain such a patient in the hospital for observation and tests for at least a day.
The basic problem, therefore, is to be able to detect an early continuing microshift of the brain relative to the cranium caused by increasing pressure of blood in a pocket or hematoma resulting from slight continuing cranial bleeding.
Use of Above Prior Art
As stated above, the usual prior art procedure for detecting brain shift relative to the cranium has been the taking of a CAT scan picture or pictures of the skull, but such CAT scan pictures do not reliably identify a very small displacement or microshift of the brain relative to the cranium.
A standard diagnostic workup includes expensive neuroimaging, i.e. CAT scan imaging or magnetic resonance imaging. Such neuroimaging may not show any shift of the brain relative to the cranium within the first hour after injury and may not detect a small blood pocket or hematoma.